Axle driving apparatus

Abstract

An axle driving apparatus for being mounted on the body frame of a vehicle and for independently rotating drive wheel members. The axle driving apparatus includes a first axle driving unit ( 18 L) having a housing ( 40 ) and a single axle ( 20 L), the single axle ( 20 L) defining a proximal end portion rotatably mounted in the housing ( 40 ) and a distal end portion extending outwardly from a first side of the housing ( 40 ). An enlarged region is defined by the housing ( 40 ), with the enlarged region extending substantially perpendicular to the longitudinal axis of the single axle ( 20 L). A hydraulic stepless speed change assembly ( 22 ) is disposed within the enlarged region. The speed change assembly ( 22 ) includes a hydraulic pump ( 52 ) having an input shaft ( 21 ) projecting from the enlarged region and includes a hydraulic motor ( 55 ) including an output shaft ( 74 ) drivingly connected to the single axle ( 20 L). The first axle driving unit ( 18 L) is used in conjunction with a second axle driving unit ( 18 R) which is adjacently disposed to the first axle driving unit ( 18 L) on the body frame of the vehicle and which is of substantially similar construction. However, the second axle driving unit ( 18 R) features a single axle ( 20 R) which extends outwardly from a second, opposite side of the housing ( 40 ) such that the axles ( 20 L, 20 R) are oppositely disposed.

1. A working vehicle, comprising:
 a prime mover having a vertical output shaft; 
 a transaxle drivingly coupled to the output shaft of the prime mover through a belt and pulley combination, wherein the transaxle includes,
 a first integrated hydrostatic transmission disposed in a first housing; and 
 a second integrated hydrostatic transmission disposed in a second housing and aligned side-by-side with the first integrated hydrostatic transmission; 
 wherein each integrated hydrostatic transmission includes,
 an input shaft extending from an upper surface of the housing and drivingly coupled to the output shaft of the prime mover through an input pulley mounted on an end of the input shaft, 
 a cooling fan mounted on the input shaft proximate to the input pulley, and 
 a hydrostatic transmission, including a pump and a motor, drivingly coupled to the input shaft and drivingly coupled to an axle which projects from a side surface of the housing; 
 
 wherein the housing of each integrated hydrostatic transmission is longer than it is wide, wherein the length of each housing extends in the direction between the pump and the axle, and the width of each housing extends in a direction parallel to the axle, and wherein the pump, motor, and axle are aligned respectively so that the pump is nearest a rear end of the vehicle and the axle is nearest a front end of the vehicle, and wherein the housing forms an oil sump having a reservoir for accommodating the expansion of oil; 
 
 a pair of driven wheels, each coupled to and driven by one of the integrated hydrostatic transmissions; and 
 a speed control arm coupled to and laterally extended from each integrated hydrostatic transmission to control the direction and speed of the driven wheels, each speed control arm having a rotational axis running parallel to a rotational axis of the axle of each integrated hydrostatic transmission; 
 wherein the output shaft of the prime mover is disposed approximately in a lateral center of the vehicle and forms a triangular arrangement with the input shafts of the integrated hydrostatic transmissions. 
 
   
   
     2. The vehicle of  claim 1 , wherein a distance between the speed control arm of the first integrated hydrostatic transmission and the axle of the first integrated hydrostatic transmission is approximately equal to a distance between the speed control arm of the second integrated hydrostatic transmission and the axle of the second integrated hydrostatic transmission. 
   
   
     3. The vehicle of  claim 1 , wherein the housing of each integrated hydrostatic transmission further comprises a mounting boss for fixing the housing to a frame of the vehicle. 
   
   
     4. The vehicle of  claim 1 , wherein the first and second integrated hydrostatic transmission are coupled to each other via a coupling mechanism. 
   
   
     5. The vehicle of  claim 1 , wherein each hydrostatic transmission of each integrated hydrostatic transmission includes a bypass mechanism allowing each axle to be in a free-wheel state. 
   
   
     6. The vehicle of  claim 1 , further comprising a mower unit drivingly coupled to the output shaft of the prime mover through a belt and pulley combination. 
   
   
     7. The vehicle of  claim 1 , wherein a rotational axis of the motor is parallel to a rotational axis of the axle and perpendicular to a rotational axis of the pump.